Fuel mixer and feed



I June 30, 1931. w. A. DANIELSON 1,812,775

FUEL MIXER AND FEED Filed Oct. 10, 1927 2 Sheets-Sheet 1 June 30, 1931. w. A. DANIELSON 1,812,775

FUEL MIXER AND FEED Filed 001;. 10, 1927. 2 Sheets-Sheet 2 Fig 2.

B9 Atty.

Patented June 30, 1931 'WILMOT A DANIELsonoF THE UNITED s'rArEs ARMY, vvnsnmeroiv, nrsrnro r OF COLUMBIA FUEVL MIXER AND FEED Application filed October 10, 1927. Serial Noi' 225,319.

(GRANTED UNDER THE ACT OF MARCH 3, 1.883, AS AMENDED APRIL 30,1928; 3700. G. 757) The invention described herein, may be manufactured and used by or for the Government for governmental purposes without payment of any royalty thereon.

This invention relates to an improved fuel mixer and feedfor furnaces or the like, and more particularly to a fuelfeed, wherein a pulverized solid fuel, a combustible gaseous fluid and air arecombinedand' fed to the point of combustion, as a highly combustible mixture. The volume and ratiolof content being under the control of the operator, part of said ratio"beinginaintained automatically, through-a single adj ustment; An object of this invention is a simple, durable and inexpensive device of the class described, wherein a relatively low cost fuel and air, forming a large'percentage of a mixture, is enriched by a relatively small percentage of highly combustible fuel of greater cost in such manner and proportion as to produce a highly combustible fuel at a relatively low cost.

A further object is to provide a fuel feeding apparatus of unit construction, which may be conveniently installed in a furnace or the like, 'at low cost and not: requiring the services of highly skilled labor.

1 further object being to provide such a construction as wiil enable to a large extent,

the use of stock material, whereby not only low initial cost, but economical replacement and repair cost, may be accomplished.

Aifurther object being to provide means whereby low cost fuel may be efiectively con sinned in a cold furnace in starting.

Another object is to provide meanswhereby high, intermediate and low temperatures, may be continuously maintained in a furnace' by the consumption of a uniformly economical fuel.

A further object being to provide a common means whereby, the volume of fuel mixture may be changed without affecting the ratio of its elements,

This and other objects will appear in the following description and be finally pointed out in the appended claims.

e Changes in form and minor details of conto provide n difications both struction may be resorted to withoutdeparts ing from the spirit of this invention.

Similar numerals indicate corresponding parts in all the figures of the drawings in which r Fig. l is a plan view of the improved fuel mixer and feed, showing a fragment of a furnace fire chamber.

2 is a vertical Fig. 1. i

Fig.3 is a horizontalsection, through the fuel. feed chamber.

Referencenow being had to the drawings by numerals, this device broadly consists of 1, a hopper adapted to contain pulverized fuel such as finely ground up coal,2, a rotary section on li11e 2-2 of 7 feed disk mounted in the feed chamber 3, a

fan l adapted to lift the pulverized fuelfrom the feed disk and discharge same through furnace feed pipe 5, means for igniting and burning the fuel'within the furnace, a fragment of the latter being shown at 6 and means for operating the device at different speeds.

A motor 7, preferably of the electrical type, provided with a controller 35, is so arranged as to operate the fan 4, the feed disk 2,'and the-hopper 1. I i y I I A fluid fuel pipe 8 is adapted to supply a highly combustible'gaseous fluid of any preferred character to the pulverized coal and air mixture, onits way to the furnace.

The above elements as shown and will now be specifically described, are for purposes of illustration only, it being understood that in arrangement of parts and their details of construction may be found more expedient, and will fall Within thescope of this invention.

The hopper 1, which may be replaced by a coal grinder or other source of pulverized combustible material (not shown) is adapted to contain a pulverized solid fuel, such as coal or other combustible material indry granularform which may be picked up and carried in suspension by a current of air.

The hopper consists of an upper stationary portion 9, of downwardly increasing area, a rotary, lower, conical portion 10, sealed at 11, to and forming a continuation, of portion 1 of the hopper, and adischarge tube 12, of

- gear to-rotate the hopper.

downwardly increasing area, at the lower end of the rotary portion 10.

Rigidly mounted at 14, on stationary portion 9 of the hopper, is an agitator rod 13, extending down intoithe rotary'hopper menu; her and terminating in the center of the upper end of discharge tube 12, which is adapted to-mai ntain a steady'flow of'the contents-of the hopper through the discharge tube. The upper stationary portion 9 of the hopper is of increasing diameter toward its bottom, to prevent clinging of the fuelto. the sides of. the hopper. The discharge tube 12 is also ofin creasing diameter toward, itsv bottom, to permit free passa e of the fuel through said tube and only a partial transmittal of pressure from the hopper to' the disk 2.

A. gear wheel t5=and the upper member of a ball bearing-16,. are mounted on, and concentric with the hopper discharge tube 12 which atits. lower end projects into the feed chamber 3.

The feed disk 2 is mounted for horizontal rotation within the chamber 8', on its vertical spindle 17. Said spindle is mounted for no tary and. liongitudinal. movement in a bearing through the top of the chamber, and is providedwith. an elongated pinion 1 8 on itsu-pper ends in meslr with, and adapted to drive The-lower end of spindle L7 is stepped in a vertically adj ustable bearing block 19, preferably screw threaded through the bottom of the feedchamber and provided with a hand wheelonits lower end, providing for the adjustment of the spindle and with it, the disk, in vertical directions.

The feed disk is of'suflicient diameter to extend beneath thel'ower end of hopper discharge tube 12, from which it receives a continuous stream of pulverized fuelfrom the hopper. The periphery of the feed disk is provided with gear teeth 21 adapted to mesh with an elongated drive pinion 2-2, mounted on feed disk drive shaft 23, mounted in the top and bottom walls of the feed chamber.

The feedl chamber 3 ispractically an air tight enclosure preferably supported on legs 24, and provided with the sealed bearing.

openings fer the hopper dischargetube 1-2 and shafts 17 and 23 and suction pipe-25 said suction pipe being in sealed communication with the intake of'fan 4, which is supported in such a maneras to provide a spacebetween the bottom ofthe-f'a-n casing and the-top of the feed chamber.

Air may be admitted to the feed chamber in numerous ways but as shown, is through a; plurality of openings 26" through the top of the chamber arranged aroundthe suction pipe 25 the-size of said openingsbeing controlled by damper 36. The air inlet openings to supply the fan and setup the suction-through suction pipe 25 must be arrangedadjacent to the suction pipe to prevent the disturbance of the pulverized fuel by currents of air, as it is carried on the feed disk from the hopper discharge. tube, to the suction pipe.

The suction pipe as above described, forms a sealed communication between the interior ofthe feed chamber and the intake of the fan and may be of' any preferred. form, such as flared or bell shaped at its lower end, its diameter and shape being determined with relation to the size of the lower end of the hopper discharge tube and the intensity of the suction desired. The lower end of the suction pipe 25, and the lower end of the discharge tube 12 are the same distance above the feed diiskQ: ZIIldE areof equal. distance from: the cen ten of notation, of the feed? disk, to cause the: fuel' deposited on the disk from the hopper discharge tube, to come directly beneath the suction pipe: as the disk rotates.

die; 1h tie of air, drawn down through openings 26 and up tl'irough suction pipe 25, and the amount of fuel depositedon the disk from the hopper, arev so proportioned, as to insure, first, a complete pick-up of all the hush deposited, second, the mostperfect combustible mixture obtainableby combiningair and pulverized. fuel: and third, the maintaining of the sameratio, throughout all adjustmentsof the disk, toward or from the hopper discharge tube 12 and suction pipe Thefan 4k is of thestaaid'ard' type arranged horizontally, and supported on and arranged slightly above the upper' surface of the feed chamber 0. The intake of the fan is as stated; above, in sealed communication with the interior of the feed chamber through suction pipe 25-, the discharge of the fan is through the furnace feed pipe 5 extending into-the lire-box of furnace 6 and is prov'ded with upwardly curvedv and inturned nozzles 27 so arranged as. to drive their respective flames into each other, thereby spreading hem. into a common formation, highly effective for heating purposes, without the c irect impingement of the flame against any part of the-furnace.

A properly combined mixture of pulverized fuel and! air alone provides a very efficient fuel under certain conditions but depend's on the: temperature of the surrounding surfaces, and cannot be considered an eiilcient fuel. for instance, if the walls of the furnace are cold, it being necessary with said mixture, to maintain high temperature in. the fire box at all times which is undesirable and-,uneconomical in many instances.

This invention contemplates providing ef fective means for supplying a comparatively 11-1? slow burning and inexpensive fuel mixture for the production of a large proportion of the desired heat, and. enriching said mixture with a comparatively small percentage of a more expensive, highly combustible gaseous dinary illuminating coal gas is fed through fluid supply pipe 8, provided with a cut-off valve 28, said pipe is preferably arranged to parallel the furnace feed pipe and from which a branch :pipe 29 controlled by valve 30 enters the furnace feed pipe with its outlet end arranged in the direction of-the disch rge end of said feed pipe.

The fluid supply'pipe 8 extends to and around the extremeend of the furnace feed pipe and terminates adjacent to the nozzles 27 and there functions, as a. pilot burner 34 operating to ignite the fuel ascaping from the nozzles, which is particularly effective I where the furnace and its walls are cold, thus providing a continuous ignition medium very essential at such times. i

The power to operate the above described fuel feed may be provided in numerous ways, one of which is by an electric motor 7, mounted on the fan casing having its shaft 31 extending down and carrying the fan blades. Said shaft also extends above the motor shell and has mounted thereon the drive pinion32, in mesh with gear 33 mounted on the upper end of shaft 23, which in turn is mounted in thefeed'chamber and through pinion 22 drives the feed disk and other parts.

-An automatic fiareback valve 35, preferably of the butterfly type, is arranged in the furnace feed pipe 5, adjacent to the fan. Said valve will remain open during the operation of the burner, but should there, for any reason, he an ignition of thefuel in'said'feed V pipe, combustion will not pass beyond valve 35 It may be stated in this connection that while the fan 4L contains a slow burning combustible mixture and the feed pipe 5, fro-m the point at which gasis admitted, to the nozzles, contains a rapid burning highly combustible mixture, the fuel in its passage through said parts will absorb heat which will insure perfect combustion at the burners, but is at a velocity greater than. flame propagation, and will prevent a back fire.

" The operation is as follows:

Ho erl is en) lied with a vulverized PP lP 1 fuel such as finel round coal from an 7 V V y 2: a convenient source not shown. In starting, gas orother fluid fuel controlled by valves 28 and 30 is permitted to pass through branch pipe 29, into furnace feed plpe 5, and through pilot burner 34, the flow of gas through the pilot is lighted and burned across the outlets of the nozzle 27, and functions as a continuous ignition means for the fuel discharge through the nozzle.

The pilot light is usually lighted at the beginning of a furnace burning period and is not extinguished until a long period ofin action is anticipated. The pilot may be con trolled by a three way valve at 30 or a separate valve 37 to permit a flow of gas only through the pilot when desired.

. The feeddisk 2 in starting is usually adjusted up relatively close to the lower ends of hopper discharge tube 12 and suction pipe 25, and by said adjustment, a mixture hav ing a relatively large proportion of highly combustible content is provided at the nozzles during the initial or firing up period.

'As the chamber of the furnace becomes heated thusproviding additional means for perfecting combustion, the percentage of slow burning and more economical contents namely pulverized coal and air may be increased and the percentage of the more expense element of the mixture, namely, gas, may be reduced, either bydiminishing the gas flow by valveBO, by lowering the feed disk and increasing the flow of pulverized coal andjair, by increasing the speed of the motor, or any or all of the above.

The adjustment of the feed disk in its relation to the lower end of the hopper discharge tube simply lengthens the angle of repose of the pulverized fuel and thereby increases the volume of discharge and at the same time increases the air passage between the lowerend of the suction pipe 25 and the disk,thus allowing a greater volume of air topassdovvn through'openings 26in the top of the chamber 3 and wipe up and thoroughly mix with the pulverized fuel which is brought from its pointof deposit on the disk to directly beneath the suction pipe, by the rotation of the disk.

The proper ratio of air and pulverized fuel to produce the best combustible mixture, r quires a sufficient volume of air to insure complete pick-up cf allthe pulverized CGE1 tent, and the parts are so adjusted and proportioned that the most effective ratio of elements will be provided and remain constant at'any adjustment of the disk.

Prior to the discovery of the above means of burning slow burning fuel such as pulverized coal mixed with air, it necessary first to heat the fire chamber of the furnace either by expensive gas heating methods or by building the ordinary fire, using wood and coal, the blast of pulverized fuel is then turned in and the furnace maintained at its maximum temperature, to insure the continued burning of the low grade fuel.

The improved fuel mixer and feed is highly effective in a cold furnace which may be tion of an economical fuel mixture, so enriched and controlled as to pro *ide an uninterrupted flow of properly proportioned fuel of a highly combustible character, in the desired quantities, at a uniformly low cost,

- under all of the above conditions.

The motor 7 through its lower shaft extension rapidly operates the fan to produce.- a blast of air at high velocity, and through pinion 32 above, drives gear and shaft 23 at a reduced speed. Pinion 22 in mesh with. teeth 21 of the disk 2 drives said disk atafurther reduced speed and pinion 18 in mesh with gear 15 again reduces the speed of the hopper.

In driving the device through the train of gearing shown, it may be accomplished by a very economical use of electrical current, since a motor of very low horse power and economical size, geared down in the manner shown, will provide the necessary power.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1-. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a hopper adapted to discharge pulverized. fuelinto said chamber, a suction pipe leading from said chamber, air inlets leading into said chamber, a fan adapted to draw a mixture of pulverized fuel and air from said chamber having an intake connected with said suction pipe and having a discharge, a furnace feed pipe connected to said discharge, burners arranged at the end of said pipe adapted to rest within a furnace, means within the mixing chamber for conveying fuel discharged from the hopper to the suction pipe, means for enriching said mixture and driving means adapted to operate said fuel conveying means and said fan.

2. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a hopper adapted to contain a pulverized fuel, having an upper stationary portion, a lower rotary portion and a tapered discharge tube arranged within the mixing chamber, a suction pipe leading from said chamber, air inlets leading into said chamber, a fan adapted to draw a mixture of pulverized fuel and air from said chamber, having an intake con nected with said suction pipe and having a discharge, a furnace feed pi 3e connected to said fan discharge and burners arranged at the end of said feed pipe adapted to rest within a furnace, means within the mixing chamber for conveying fuel discharged from the hopper to the suction pipe, means for enriching said mixture and driving means adapted to operate said fuel conveying means and said fan.

ber arranged with its lower endwithin said.

chamber in linewith the lower end of the hopper discharge tube, air inlets leadinginto.

said chamber, a fan adaptedto draw a mix-- ture of pulverized fuel and air from said chamber having an. intakev connected with said suction pipe and having a discharge, a

furnace feed pipe connected to said fan discharge and burners arranged at the end of said feed pipe adapted to rest within a furs naee, means within the mixing chamber for conveying fuel discharged from thehopper to the suction pipe, means for enriching said. mixture and driving means adapted to opcrate said conveying means and said fan,

4. A fuel mixer and feed for furnacesv or the like, comprising a mixing chamber, a hopper adapted to discharge pulverized fuel into said chamber having a discharge tube with its lower end arranged within said chamber, a suction pipe leading from said chamber with its lower end arranged in line, with the lower end of thehopper discharge tube, air inlets leading into said chamber, means for controlling thefiow of air through said inlets, a fan having its intake connected, to said suction pipe and adapted to draw mixture of pulverized fuel and' air from said chamber and having adischarge, a furnace. feed pipe connected to-said fan discharge and burners arranged at the end of said feed pipe adapted to rest within a furnace, means for conveyingfuel' discharged from the hopper tube to the suction pipe, driving means adapted cooperate said conveying means: and said fan and means for enriching said mix.- ture after leaving the mixing chamber.

5. A fuel, mixer and feed for furnaces: or the like, comprising a mixing chamber, a hopper adapted. to dischargepulverized fuel into said chamber, having an upper tapered stationary portion, a lower rotary portion and atapered discharge tube arranged with its lower end within the mixing chamber, a stationary agitator rod mounted on said stationary portion of the hopper and extending to said discharge tube adapted to agitate the contents of said hopper, a suction pipe leading from said chamber having a flared lower end arranged within said chamber'in line with the lower end of said hopper discharge tube, a fan adapted todraw a mixture of pulverized fuel and air from said chamber having its intake connected with said suction pipe, a furnace feed pipe connected to said fan discharge and burners at the end of said feed pipe adapted to rest within a furnace, means for conveying fuel discharged from the hopper to the suction pipe and means for nace feed pipe adapted to draw a mixture of the like,

. adapted to enriching said mixture during its passage through the furnace feed pipe. 7

6. A fuel mixer and, feed for furnaces or comprising a mixing chamber, a hopper adapted to discharge pulverized fuel into said chamber, a suction pipe leading from said chamber, air inlets leading into said chamber, means for drawing a mixture of pulverized fuel and air from said chamber and discharging same into a furnace, and a vertically adjustable disc arranged within said chamber beneath said hopper discharge and suction pipe adapted to convey pulverized fuel discharged from the hopper to the suction pipe and control the amount of pulverized fuel deliveredvinto said chamber. 7. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a hopper adapted to discharge pulverized fuel into said chamber having a discharge tube with its lower end arranged within the chamher, a fan having an intake and a discharge, a suction pipe leading from said chamber connected with the intake of the fan and having its lower end arranged in line with the lower end of the hopper discharge tube, a rotary conveyor arranged with the mixing chamber and extending beneath the hopper discharge tube and the suction pipe,

convey pulverized fuel from beneath the discharge tube to beneath the suction pipe, air inlets leading into the mixing chamber around the suction pipe, a furnace feed pipe connected to the fan discharge adapted to discharge a mixture of pulverized fuel and air to a furnace, and means for enriching said mixture on its Way through said furnace feed pipe.

8. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a hopper adapted to contain pulverized fuel having a discharge tube with its lower end arranged apre-determined distance within the mixing chamber, a suction pipe extending through the top of the mixing chamber with its lower end in line with the lower end of the hopper of the discharge tube, a furnace feed pipe having burners at its end, a rotary disk mounted within the chamber adapted to extend beneath said hopper discharge tube and said suction pipe, means for adjusting said disk vertically to control the flow of fuel from the hopper, a fan connected with said suction pipe and said furpulverized fuel and air from said chamber and discharge it through said ,furnace feed pipe, and means for enriching said mixture between the fan and the burner.

9. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber having feed inlet and outlet openings, a hopper adapted to discharge pulverized fuel into said chamber a movable member within said mixing chamber adapted to receive said pulverized fuel and deliver same to the outlet opening, a suction pipe leading from the outlet opening of said chamber, air inlets surrounding said suction damper leading into said chamber, a fan adapted to draw a mixture of pulverized fuel and air from said chamber having its intake connected with said suction pipe and its discharge terminating in burners adapted to be arranged within a furnace, a fluid fuel supply pipe adapted to discharge an enriching liquid fuel into said mixture passage through the fan discharge, and means for igniting the flow of fuel from the burners.

10. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a rotary feed disk mounted on a vertical spindle within the mixing chamber, a pulverized fuel hopper having a discharge tube with its lower end arranged within said mixing above said disk adapted to discharge fuel on said disk, a suction pipe arranged with its lower end within the mixing chamber in line with the lower end of said hopper feed tube and a distance from the center of rotation of the feed disk equal to that of said hopper discharge tube, a rotary fan with its intake connected with said suction pipe having its discharge provided with a furnace feed pipe terminating in burners, means for driving the fan and the feed disk, means for controlling the mixture of pulverized fuel and air from the chamber, and means for enriching said mixture after it leaves the mixing chamber. 11. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a rotary feed disk arranged within the chamber, a hopper having a discharge tube arranged within the chamber above the feed disk and adapted to discharge pulverized fuel on the disk, a suction pipe having its lower end arranged in line with the lower end of the hopper discharge tube a corresponding distance from the center of rotation of said disk adapted to pick up said pulverized fuel from said disk, air inlets arranged in the casing around the suction pipe, a fan having its intake connected with the suction tube and its pipe and controlled by during its llU discharge adapted to be arranged within a 1 furnace, means adapted to raise and lower the feed disk to increase or diminish the distance between the disk and the lower ends of the hopper discharge tube and the suction pipe and thereby control the flow of pulverized fuel from the hopper of air through the suction pipe, means for adding an enriching fluid fuel to the mixture on its way to the furnace, means for operating the fan, the rotary feed disk and the rotary portion of the hopper, and means for controlling the speed of the motor.

12. A fuel mixer and feed for furnacesor V the like, comprising a mixing chamber, a vertically adjustable feed disk rotatably mountl ed within the mixing chamber, a hopper having an upper stationary and a lower rotary portion, an agitator arranged within the hopper, a discharge tube extending from the hopper arranged with its lower end within the chamber a short distance above said rotary disk and adapted to deposit pulverized fuel on the disk, a suction pipe in sealed communication with the interior of the mixing chamber with its lower end in line with the lower end of the hopper discharge tube at a distance from the center of rotation of said disk, equal to that of said hopper discharge tube, a vertically adjustable bearing arranged beneath said feed disk adapted to adjust said feed disk to increase or diminish the space between said feed disc and the lower ends of the hopper discharge tube and the suction pipe, air inlet openings into the feed chamber arranged around said suction pipe, a fan having its intake in sealed communication with the suction pipe and a discharge pipe terminating in burners, said fan adapted to draw a. mixture of pulverized fuel and air from the feed chamber and direct it to said burners, a iiuid fuel supply provided with a branch extending into said fan discharge pipe adapted to add an enriching element to the mixture of pulverized fuel and air and having an extension adapted to supply said enriching fluid to said burners for continuous ignition of the fuel discharged from the burners.

13. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a pulverized fuel hopper having a discharge tube arranged a pre-determined distance within the hopper, a suction pipe in sealed communication with the interior of said chamber adapted to extend therein a distance corresponding to that of said hopper discharge tube and having a flared lower end, a disk rotatably mounted within the mixing chamber and adapted to extend beneath said discharge tube and suction pipe adapted to con vey pulverized fuel deposited on said disk from said discharge tube to beneath said suction pipe, a rotary fan having its intake con nected with the outer end of said suction pipe and its discharge terminating within a furnace, air inlets in the mixing chamber adjacent to said suction pipe adapted to direct currents of air in such a direction as to pick up the pulverized fuel delivered to the suction pipe by said disk, means for adjusting the disk toward and from the lower ends of said discharge tube and said suction pipe for the purpose of controlling the flow of pulverized fuel from said tube and the flow of air through said suction pipe and means for rotating said disk and said fan.

14. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a hopper adapted to contain pulverized fuel having a discharge pipe extending into the chamber,

a suction pipe extending into said chamber, a fan having an intake connected with the outer end of said suction pipe and a discharge, a furnace feed pipe connected to said discharge, a conveyor movable beneath the hopper discharge and suction pipes adapted to convey pulverized fuel deposited thereon from the hopper discharge to the suction pipe and means for adjusting said conveyor to control simultaneously the flow of pulverized fuel to the conveyor and the flow of air through the suction pipe.

15. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a hopper adapted to contain pulverized fuel having a discharge pipe extending into the charm ber, a fan having an intake and a discharge, per, a fan having an intake and a discharge, said intake being connected with said suction pipe, a conveyor arranged beneath said discharge and said suction pipe adapted to receive pulverized fuel from the hopper and convey it to beneath said suction pipe, means for simultaneously controlling the flow of pulverized fuel to the conveyor and air through the suction pipe and independent means for controlling the flow of air through the suction pipe.

16. A fuel mixer and feed for furnaces or the like, comprising a mixing chamber, a hopper adapted to contain pulverized fuel having a discharge pipe extending into the chamber, a suction pipe extending into said chamber, afan having an intake and a discharge, said intake being connected with said suction pipe, a conveyor arranged beneath said discharge and said suction pipe adapted to receive pulverized fuel from the hopper and convey it to beneath said suction pipe, means for enriching said mixture on its way to the furnace, means for controlling the amount of the enrichment, means for simultaneously controlling the flow of pulverized fuel to the conveyor and air through the suction pipe by a movement of the conveyor and independent means for controlling the flow of air through the suction pipe.

WILMOT A. DANIELSON. 

